Cathode ray tube for processing digital data



E. J. SMURA 3,092,746

CATHODE RAY TUBE FOR PROCESSING DIGITAL DATA June 4, 1963 3 Sheets-Sheet 1 Filed July 18, 1960 RELATION 0F POTENTIAL 0N PLATES II? AND I9 WITH OTENTIAL 0N ANODE I21 CATHODE T0 ANODE DISTANCE IN CENTIMETERS 2525? 22 ZCZEE $0 50 A 7' TORNE Y FIG. 3

E. J. SMURA 3,092,746

CATHODE RAY TUBE FOR PROCESSING DIGITAL DATA June 4, 1963 3 Sheets-Sheet 2 Filed July 18, 1960 FIG.

June 4, 1963 E. J. SMURA 3,0 ,7

CATHODE RAY TUBE FOR PROCESSING DIGITAL DATA Filed July 18, 1960 s Sheets-Sheet a nmw udjw W g 235Y =-236Y f N \4 9 201x 3; G (M1 TM NI v v v Cg 3 2 6* 'Lmwtim FIG. 9

3 9 6 7 CATHODE RAY TUBE FOR PROCESSHQG DIGHTAL DATA Edwin J. Smura, Apalachin, N.Y., assignor to International Business Machines Corporation, New York, N.Y., a corporation of New York Filed July 18, 19%, Ser. No. 43,672

6 Claims. (Cl. 313-35) The present invention relates to cathode ray tubes and more particularly to cathode ray tubes for processing digital data.

There is a present need in the digital computer field, as well as in the electronics art in general, for cathode ray tubes of relatively small size which can provide sulficient current in the beam to selectively drive devices such as cores, transformers, transistors, etc.; it is desirable that such cathode ray tubes include sensitive con trols for selectively deflecting the electron beam to one of a plurality of anodes as desired.

Accordingly, it is a principal object of the invention to provide an improved cathode ray tube for providing an electron beam having relatively large current therein and which beam may be sensitively controlled.

It is another object of the invention to provide an improved electron lens structure.

It is yet another object of the invention to provide an improved electron beam deflection system.

In a preferred embodiment of the invention, a cathode ray tube is provided having improved electrode elements for producing a sheet beam and controlling the beam to selectably impinge on one of a plurality of anodes at a given instant. The electron lens for the tube include apertured stops positioned internally within the lens to control beam abberations without disturbing the focusing field. Plates for vertically deflecting the beam are distributed along the path of the beam and are connected directly to digital input lines, thus eliminating digital to analogue converters. The beam is deflected according to the incoming code and impinges on distributed tabs to energize core or other type of matrices.

The foregoing and other objects, features and advantages of the invention will be apparent from the following more particular description of preferred embodiments of the invention, as illustrated in the accompanying drawlugs.

In the drawings in which like reference characters refer to like elements throughout:

FIG. 1 is a schematic diagram of an envelope of a cathode ray tube according to the invention;

FIG. 2 is a more detailed drawing of the cathode electrode of the cathode ray tube according to the invention.

FIG. 3 is a graph useful in explaining the relation of the control voltage applied to the drive plates and the cathode-to-anode spacing and voltage differential;

FIG. 4 is an isometric view of a lens system of the cathode ray tube according to the invention;

FIG. 5 shows the field configuration developed around the focusing lens and the relative position of the apertured stops;

FIG. 6 is a side view of a cathode ray tube in accordance with the invention particularly showing the electron beam deflecting plates;

FIG. 7 is a fragmentary front view of a cathode ray tube in accordance with the invention showing the anode tabs;

FIG. 8 is a schematic diagram of a matrix of a type which may be driven by cathode ray tubes in accordance with the invention;

FIG. 9 shows a circuit for connecting the anode tabs to the matrix to be driven.

fire FIG. 1 shows an evacuated envelope 111 in which the various electrode elements of a cathode ray tube 114 are mounted. In one particular embodiment, the envelope is rectangular in form, the width of the envelope is about 5 /2 inches, the length is about 3% inches, the height varies from about A; inch at the neck 111c of the tube to about 1% inches at the face lllb of tube 110. For ease of assembly, the envelope 111 is formed in two separate pieces and joined along line 111a after the electrode elements. are mounted in position. Also, one half of the electrode elements may be mounted on one half of the envelope and the other mating half of the elements may be mounted on the other half of the envelope and positioned in place when the envelope halves are joined.

Referring to FIGS. 2 and 6, a cathode 113, in the form of a rectangle, is positioned at the neck end, the left-hand end as oriented in FIG. 1, of envelope 111. The cathode comprises a nickel sleeve on which an oxide coating has been deposited. A heater filament 115 is aflixed along the length of the cathode 113 and is connected to a source of energy of any suitable type, not shown. In the one particular embodiment, cathode 113 is about 4 /2 inches in length and inch in width.

A pair of beam-forming plates 117 and 119 are mounted in parallel relation and at a 67.5 angle with respect to the axis of the cathode ray tube, as is known in the art, to form a sheet beam. In the one particular embodiment, plates 117 and 119 are about 4 /2 inches in length and inch wide and are separated from the cathode by about V inch. The beam-forming plates 117 and 119 are utilized for driving or controlling the beam as Well as for forming the beam. Plates 117 and 119 have a voltage applied thereto which is approximately 100 volts negative relative to cathode 113 when it is desired to cut off the tube and are raised to cathode potential when cathode emission is desired. By way of example, an electrical circuit for providing the foregoing voltages to plates 117 and 119 is shown in FIG. 2. In FIG. 2, there is shown a battery having its positive terminal connected to ground reference and its negative terminal connected through switch 176 and leads 177 and 178 to plates 117 and 119' respectively. Cathode 113 is shown as being connected to ground reference.

For computer or data processing application, only two operating states of cathode 113 need be considered, namely, the cathode is either energized to produce an electron beam or it is cut off, that is, deenergized. By also utilizing the beam-forming plates 117 and 119 as control elements, a relatively lower drive voltage than heretofore necessary can be applied to control the on-otf condition of the cathode while still maintaining rectilinear flow. Second, plates 117 and 119 provide a relatively high input impedance, due to the fact that the plates see only electrons in transit moving away from them. As is known, if an element sees electrons both moving toward and away therefrom, a higher displacement current results with a consequent lower input impedance as the frequency increases. \Vhen electron transit time is of the same order as the signal duration, the amplitude of displacement current in the leads connected to plates 11? and 119 approaches the amplitude of the electron current from the cathode 11-3.

Referring to FIG. 6, an anode 121 is positioned in front of cathode 113 for accelerating the electron beam.

The current is determined by the following known equation which relates the applied voltages with the cathodeto-anode spacing:

3 2 I=GQV AQ% where I is the beam current, G is beam perveance, V is the voltage diiferential between the cathode and the anode,

A is the area of the cathode, and X is the distance between the anode and cathode.

As will readily be appreciated, the spacing between the anode and the cathode affects the voltages that must be applied to the plates 117 and 119 to cause the cathode to shift from its on, that is, beam emitting, to its cut-off condition, and consequently determines the amplitude of the signal or control voltages which must be applied to plates 117 and 119. FIG. 3 shows a plot of cut-off potential anode potential versus cathode-to-anode distance in centimeters. The field plot is obtained by locating a zero potential point on the axis of the tube and away from the cathode. Cut off denotes no space charge; the zero point lies a sufficient distance away from the cathode to adequately represent this condition. Since moving the anode closer to the cathode increases the emission, the anode voltage must be reduced to provide a constant current output from the cathode. If the anode voltage is reduced, the potential which must be applied to the plates 117 and 119 to cut-off cathode 113 can be reduced. However, as can be seen from the sharp break in the curve at about 7.5 centimeters, any further reduction of the cathodeto-anode distance requires a proportionally much higher potential to be applied to plates 117 and 119 to control, that is, cut-01f cathode 113.

Referring now to FIGS. 4 and 5, an electron lens system 130 including electrostatic lenses 129, 131 and 133 of a type commonly referred to as univoltage or unipotential lens focuses the electron sheet beam. For purposes of ease of assembly, as explained above, the lens are each formed in two separate parts. Lenses 129' and 133 are formed in the shape of channel members and the channels are then mounted with the free ends of the channel facing one another; with a spacing therebetween. The upper part of lens 131, as oriented in the drawing, is also electrically or potentially separated from the lower part of the lens for purposes to be described hereinbelow. Lens 131 is provided with a potential higher than that of lenses 129 and 133 to develop the necessary field configuration as shown in FIG. 5 in which the dotted lines represent the potential distribution or flux lines provided by the lens. As seen from FIG. 5, a pair of flux or potential lines or planes 140 and 143 are in a plane parallel to the lens, that is, the potential along this plane is independent of the distance away from the axis of the tube. The field plots may be obtained in any suitable, well-known manner.

In accordance with the invention, one or more apertured members or stops 132 and 134 are positioned intermediate the lens to limit the off-axis rays due to, for example, chromatic abberations and/or thermal velocities. The size of the aperture in each of stops 132 and 134 is equal to twice the distance between lenses 129 and 131 or between lenses 131 and 133. Apertured stop 132 is positioned intermediate lenses 129 and 131, with the distance from stop 132 to lens 131 being about twice the distance from stop 132 to lens 129. Note, the FIGS. 4, 5 and 6 are not all to exact scale but are representative. Apertured stop 134 is positioned in relatively the same position betwen lenses 131 and 133 as stop 132 is positioned between lenses 129 and 131. When stops 132 and 134 are inserted or positioned in the foregoing manner, the stops will lie along lines or planes 140 and 143 and will not affect the flux or potential field. The positioning of the stops 132 and 134 will be independent of the aperture size and the potential applied to the lens provided the distance between lens 131 and lens 129, and between lens 131 and lens 133, is equal to one half of the size of the aperture in the stops. Insertion of the aperture stops along planes 140, 143 allows analysis for smallest spot size at the required focal length without recomputation. Thus, even though the lens are scaled up in size, passage of the beam can be obtained by inserting the aperture stop along the forgoing planes. This provides a maximum passage of the current with the smallest possible spot size on the screen or face of the tube. Also, by positioning the stops within the lens system, the overall length of the tube is reduced while maintaining a given focal length as opposed to prior art tubes which have the stops disposed externally of the lens.

As is known, computation of the trajectory of the electron beam, considered as a light beam passing through an idealized lens such as in optics, provides a plane of least confusion, that is, a vertical plane wherein all the beams converge to provide a minimum diameter crosssection or waist. The stops 132 and 134 are arranged to provide a focusing action by changing the plane of least confusion, that is, by stopping those electrons which enter the lens at the widest angle from passing through thelens. The smaller the aperture in stops 132 and 134, the longer the focal length and consequently the sharper the focusing action. However, as the size of the apertures in stops 132 and 134 is decreased, a proportionally larger portion of the beam is limited, that is, stopped, with a consequent decrease in the current and in the brightness of the spot on the face of the cathode ray tube.

Moreover, as is also known, because of the electron repulsive forces in the electron beam, the electrons do not move in straight lines but their paths are actually parabolic. It has been found that the actual point at which the beam has a minimum waist thickness is extended outward to approximately twice the distance from the value which is obtained considering the electron beam as a light beam. In practice, the sheet beam is focused by correlating the potential applied to the lens and the size of the aperture to provide a desired spot size with optimum current and a minimum of aberrations on the face of the cathode ray tube.

Although the lens is described as a symmetrical focus driver, by keeping one part, say the upper part, of lens 131 one potential, and the other, say the lower part, of lens 131 at double the symmetrical focus potential, the focusing action will occur at approximately the same focal length as that derived in the symmetrical focus case. The deflecting arrangement can thus be arranged for a binary code.

The plates for deflecting the electron beam to impinge at the desired spot on the face 111b of the cathode ray tube are numbered individually as -168. As will be appreciated, plates 150-168 are rectangular in form and extend across the width of tube 110; FIG. 6 shows an end view of the plates. External control circuitry of any suitable known type, not shown, provides selected potentials to the deflecting plates to deflect the beam to impinge on a selected one of a plurality of anode tabs formed on the face or screen 111b of tube 110 which tabs are collectively indicated as 70, see FIGS. 1 and 6.

When the electrons pass out of the lens region, the electrons first enter the region of the deflecting plates 150 and 151. The upper and lower parts of lens 131 are electrically cross connected by leads 136 and 138 respectively with the deflecting plates 150 and 151. If it is assumed that a positive potential is applied to plate 150 with respect to plate 151, the bottom portion of the beam is focused toward the top portion; this permits the beam to clear the other deflecting plates in its path toward the face of the tube and to come to a proper focus after curvature of flight. Likewise, if a positive potential is applied to plate 151 with respect to plate 150, the top portion of the beam is focused into the bottom portion similarly as described above.

From the following table, it can be seen that various combinations of potentials or control signals applied to the third terminal of switch 172 is connected to ground reference.

It will be appreciated that a circuit equivalent to circuit 170 will be separately connected to each of the deflecting the deflecting plates effect a coded, visual indication of 5 plates 150-168. the signals, that is, the electron beam can be controlled It will be appreciated that potentials on the deflecting to impinge on a selected one of 32 anode tabs. For eX- plates 150168 control the path of the electron beam ample, to energize the anode tab numbered 9, potentials from the time the beam leaves the lens region until it are applied to the deflecting plates as follows: plate 150 impinges on the face 111b of the tube 110. Also, the would be positive, plate 151 would be at zero potential, 10 deflecting plates are at all times rather close to the path plate 154 would be positive, plate 152 would be at zero of the beam so that relatively low potentials can be appotential, plate 155 would be at Zero potential, plate plied to the plates and yet precise control of the path of 156 would be positive, plate 158 would be at a negative the beam can be obtained. potential, plate 159 would be positive, and all the other A Significant feature of the tube n accordance With plates would be at zero potential. Thus, there is obthe invention is that the maximum Operating Potehtia1 tained a transfer tree type of switching, as is well known f Screen lllb iS 1500 volts, 3 relative low voltage in iI1 the in which :1 i g input may be transferred to the cathode ray tube art, and the current of the electron any one of a number of outputs. See as a general refbeam iS approximately 150 miiiial'hpefes Which is a relaerence pages -54 of The Design of Switching Circuits tiVeiY high current in the Cathode y tube by Keister, Ritchie and Washburn; D. Van Nostrand Co., 20 A basic form of one p of Output circuitry Which Inc., published 1951. may be driven by a plurality of tubes each constructed in Table Anode Tab Deflecting Plates Number 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 o 0 0 0 0 0 0 0 0 0 0 0 0 O 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 o 0 0 0 0 0 0 0 0 0 0 0 0 0 o 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 o 0 o 0 0 0 0 0 Defleeting Plates Anode Tab Number 0 0 0 0 0 0 0 0 0 0 o 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 o 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 o 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 o 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 e indicates a relatively positive potential applied to a deflecting plate.

(0) indicates a zero potential applied to a deflecting plate The deflecting plates are arranged so that the voltages 60 accordance with the invention is shown in FIG. 8, which applied to all the deflecting plates are the same and all the plates may be energized or driven by transistor or tube circuits of any suitable type known in the art. Since the driving circuits for the deflecting plates are well known in the art and are per se not a part of the invention, they are not shown. By way of example, a simplified circuit 170, which is electrically equivalent to the aforementioned transistor or tube circuits for driving the deflecting plates 150168 is shown in FIG. 6. The circuit 170 includes a center grounded battery 171 connected by way of a three-way switch 172 to deflecting plate 165 for providing positive, (0) ground, and negative potentials to plate 165. The positive terminal of battery 171 is connected to one terminal circuitry is the subject of copending patent application Serial Number 43,385 of E. J. Smura filed on July 18, 1960, for Matrix and assigned to the same assignee as the present invention.

For purposes of ease of explanation, a relatively simple matrix configuration 211 is shown in MG. 8. The matrix 211 is driven by a total of 16 tubes; only two anode tabs of each tube being utilized in this particular showing.

In FIG. 9, there is shown a circuit including a transformer 240 used for coupling the anode tabs to drive the matrix 211; all the transformers are similar so that a description of transformer 240 which couples anode tabs numbered 1 and 2 of tube 201X to matrix 211 is necessary. Transformer 240 comprises a primary winding of switch 172, the negative terminal of hatter 171 75 241, a secondary winding 242 and a tertiary winding 243. Magnetic material 240a having no sharply defined is connected to the second terminal of switch 172, and

remnant flux state inductively couples the primary winding 241 to the secondary winding 242; and magnetic switching material having two stable remnant flux states such as a magnetic or ferrite core 24% couples the secondary Winding 242 to the tertiary winding 243. Primary winding 241 has one terminal connected to anode tab number 1 in tube 201X, and its other terminal connected to anode tab number 2 of tube 201X; the midpoint of winding 241 is grounded. The upper half of winding 241, that is, the portion extending from anode tab number 1 to ground, is wound in a first direction, say, counterclockwise, around transformer material 2400; the lower half of winding 241 which extends from ground to anode tab number 2 is wound in the opposite or clockwise direction around transformer material 24ila. Secondary winding 242 has one terminal connected to ground and the other terminal connected to drive line 221X. Tertiary winding 243 has a resistor 244 connected thereacross. Resistor 244 is selected to match the characteristic impedance of line 221X and thus prevents any energy received through 221X from being reflected back down the line for purposes which will be evident hereinbelow. For current less than a given amplitude, as will be explained hereinbelow, the magnetic core 2411b provides zero coupling between the secondary winding 242 and tertiary winding 243 such that the tertiary winding does not affect the operation of the circuit. For currents above a given amplitude, the core 24% will switch or change stable states and thereby couple energy to the tertiary winding which energy is dissipated by resistor 244.

The upper half of winding 241 is utilized as the write line and the lower half of winding 241 is utilized as the read line. As seen, the odd numbered anode tabs in the cathode ray tubes may be used to write and the even numbered anode tabs may be used to read. As is known, the write and read operations in the matrix are essentially similar with the binary element being driven to one stable state during the Write operation and being driven to the other stable state during the read operation.

Tubes 201X208X comprising the X drive group have their deflection plates electrically connected in parallel, thus the electron beam is directed to impinge on the same respective anode in each tube at a given instant. Likewise, tubes 201Y-208Y have their deflection plates electrically connected in parallel such that the electron beam is directed to impinge on the same respective anode in each tube at a given instant.

The tubes 201X208X and 201Y-208Y are controlled to be on or off, that is, the tubes are controlled to have an electron beam being emitted from the respective cathode of a tube and impinging on one of the anode tabs, or the electron beam is not being emitted, that is, the beam is cut off.

The writing operation of the matrix is as follows. Assume that it is desired to energize the core designated at 213Q in matrix 211 which core is in an initially neutral state. Tubes ZillX-ZMX and 206X-208X, that is, all the tubes in the X group except tube 205X will be controlled to be on or conducting. Likewise, tubes 201Y 204Y and 206Y208Y, that is, all the tubes in the Y group except tube 205Y will be controlled to be on. All the on tubes will be addressed such that the electron beam is directed to impinge on anode number 1. Thus, in tube ZillX, for example, a current I will be caused to flow in transformer 240 from anode number 1 through the upper part of winding 241 to ground reference. A current NI, indicated by the solid arrow, will flow in the secondary winding 242 due to transformer action, N being the current transfer ratio of the transformer. The current path is from ground through secondary wind ing 242, drive line 221X to the common line 229 and point A. Likewise, in each of the tubes which are turned on in the X and Y drive groups, the current impinging on anode number 1 will cause a current I to flow in the respective primary winding inducing a current N1 in the secondary winding which flows in the direction shown by the solid arrows in the respective drive line. Note, in this case, that all the X drive lines except drive line 225X will be energized by the respective transformer to have current flowing therein. The current in drive lines 221X-224X and 226X-228X will flow toward and be summed in common line 229, in this particular case at junction point A. A total current of 7NI will thus be flowing into junction A. From Kirchhoffs law, it will be appreciated that the sum of all the current flowing into junction A must equal the sum of the current flowing away from junction A. Therefore, all the currents flowing into junction A will be summed and a total current 7NI will flow away from junction A, through drive line 225X and the secondary winding 251 of the transformer 250 associated with tube 205X to ground. The total current 7NI in the secondary winding 251 will cause the core material of transformer 250 to switch magnetic states and cause tertiary winding 243 to induce current to flow into load resistor 250R. Since resistor 250R is matched to the characteristic impedance of line 225Y, it will dissipate all the energy flowing in the line and no current will be reflected back.

Likewise, for the Y group of drive lines, all the Y drive lines except drive line 225Y will be energized by the respective transformer to have current flowing therein. A current NI will flow in lines 231Y234Y and 236Y 238Y toward a common line 239 and junction B. At junction B, all the currents will be summed and a total current 7NI will flow down drive line 235Y through the secondary winding 241 of the transformer 260 associated with tube 205Y. The total current 7NI in the secondary winding 261 will cause the core material of transformer 260 to switch magnetic states and cause tertiary winding 262 to induce a current 7NI to be dissipated in resistor 260R.

The current flow through the X and Y groups of drive lines is arranged to be concurrent, therefore, it will be obvious that a total current of 14NI will be passing through the desired core 213Q. The total current 14NI flowing through core 213Q is sufficient to energize core 213Q and cause it to shift from one to the other of its stable states.

The reading operation is similar. For reading, the desired tubes are addressed such that the electron beam is caused to impinge on anode number 2 in each tube and the current is induced to flow through the drive lines in a reverse direction relative to that of the writing operation, as shown by the dotted arrows.

A suitable sensing line 270 of any well-known type is wound through each of the cores in series such that a writing or reading operation is sensed when a selected core shifts from one to the other of its stable states.

Referring back to FIG. 6, although in the embodiment shown, a triode configuration, namely cathode 113, plates 117 and 119, and anode 121 are used, it will be appreciated that a second anode similar to anode 121 might be added to control the current drawn from the cathode and, at the same time, impart a sufficiently high velocity to the electron beam.

Referring now to the deflecting plates -168 and, as indicated above, in a high density relatively slow velocity cathode ray tube the coulomb repulsion in the beam gives rise to a divergence of the beam; a second factor which gives rise to divergence of the beam is a drop in the space potential through which a beam drifts. It has been found that since plates 156-168 are relatively close to the electron beam throughout its path tlnough the drift space the divergence due to the second factor is not significant. It has also been found that, if the plates 150168 are removed, the divergence of the beam due to the second factor is considerable.

While the invention has been particularly shown and described with reference to preferred embodiments 9 thereof, it will be understood by those skilled in the art that the foregoing and other changes in form and details may be made therein without departing from the spirit and scope of the invention.

What is claimed is:

1. A cathode ray tube for processing digital data comprising an electron gun including a cathode, a pair of plates positioned at an acute angle with the plane of the cathode for forming a sheet beam, said plates being spaced from said cathode, means for said plates being arranged for providing on-off control of the emission from said cathode, means for accelerating the electron beam, an electron lens system for developing a potential field for focusing the electron beam onto the face of the tube, said lens system comprising at least three apertured lenses positioned transversely to the electron beam, first apertured stop means positioned intermediate the first and second of said lens, second apertured stop means positioned intermediate the second and third of said lens, said stop means being positioned so as not to disturb the focusing field developed by said lens, a plurality of electron beam deflecting plates for controlling said beam to impinge at selected points on the face of the tube, said plurality of plates being positioned in spaced relation in a truncated-cone-like arrangement with a row of two deflecting plates forming the narrow end of the cone and being positioned adjacent the lens system, a row containing the largest number of deflecting plates positioned adjacent the face of the tube, said deflecting plates providing a transfer tree type of deflection in which the electron beam is routed to any one of a plurality of points on the face of the tube according to the combination of potentials applied to said plates, and a plurality of anode tabs on the face of the tube each arranged to provide an output when the electron beam impinges thereon.

2. A cathode ray tube for processing digital data comprising means for forming a sheet beam and accelerating said beam toward the face of the tube, an electron lens system, said lens developing a potential field for focusing the electron beam onto the face of the tube, said lens system comprising three apertured lenses positioned transversely to the electron beam, first apertured stop means for providing a focusing action and minimizing aberration by limiting stray beams being positioned intermediate the first and second of said lens in a plane in which the field forms a straight line between said first and second lens so as not to affect the field distribution and thus the focusing action of said lens, the size of the apertures in said stop means being equal to the distance between said first and second lens, second apertured stop means similar to said first stop means positioned intermediate the second and third of said lens in a relative same position as said first stop means is positioned between said first and second lens, a plurality of electron beam deflecting plates for controlling said beam to impinge at selected points on the face of the tube, said plurality of deflecting plates being arranged in rows in a truncated-cone-like arrangement with a row comprising a pair of plates forming the narrow end of the cone and being positioned adjacent the lens system, a row containing the largest number of deflecting plates forming the base of the cone and positioned adjacent the face of the tube, said deflecting plates providing a transfer tree type of deflection in which the electron beam is routed to any one of a plurality of points on the face of the tube according to the combination of potentials applied to said plates, and a plurality of anode tabs on the face of the tube each arranged to provide an output when the electron beam impinges thereon.

3. A cathode ray tube for processing digital data comprising an electron gun including an elongated cathode, a pair of spaced plates positioned along the length of said cathode at an acute angle with the plane of the cathode for forming a sheet beam, said plates being spaced from said cathode, said plates at times being at a positive potential relative to said cathode for providing on-oif control of the emission from said cathode, means for accelerating the electron beam, an electron lens system, developing a potential field for focusing the electron beam onto the face of the tube, a plurality of electron beam defleeting plates for controlling said beam to impinge at selected points on the face of the tube, said plurality of plates being positioned in spaced relation in a truncatedcone-like arrangement with a row of two deflecting plates forming the narrow end of the cone and being positioned adjacent the lens system a row containing the largest number of deflecting plates positioned adjacent the face of the tube, and said deflecting plates providing a transfer tree type of deflection in which the electron beam is routed to any one of a plurality of points on the face of the tube according to the combination of potentials applied to said plates.

4. A cathode ray tube for processing digital data comprising an electron gun including an elongated cathode, a pair of spaced plates positioned along the length of and straddling said cathode and at an acute angle with the plane of the cathode for forming a sheet beam, said plates being spaced from said cathode, said plates providing onolf control of the emission from said cathode, means for accelerating the electron beam along the axis of the tube, an electron lens system for developing a potential field for focusing the electron beam onto the face of the tube, said lens system comprising at least three apertured lenses positioned transversely to the electron beam, first apertured stop means positioned intermediate the first and second of said lens, second apertured stop means positioned intermediate the second and third of said lens, said stop means being positioned in a plane in said field whose potential is independent of the distance from the axis of the tube, said stop means providing a focusing action for the electron beam and also limiting stray rays caused by various effects including chromatic aberrations and thermal velocities, and a plurality of deflecting plates for controlling said beam to impinge at selected points on the face of the tube.

5. A cathode ray tube for processing digital data comprising means for forming a sheet beam and accelerating said beam toward the face of the tube, an electron lens system for focusing the electron beam onto the face of the tube, a plurality of electron beam deflecting plates, said plurality of deflecting plates being arranged in a truncated-cone-like arrangement with a pair of deflecting plates forming the narrow end of the cone and being positioned adjacent the lens system, the second row comprising three plates, the third row comprising five plates, the fourth row comprising nine plates positioned adjacent the face of the tube, the center plate of the second, third and fourth rows being positioned substantially along the axis of the tube, said plates having first, second or third amplitude voltages selectively applied thereto for controlling the path of the beam, said deflecting plates providing a transfer tree type of deflection in which the electron beam is routed to any one of a plurality of points on the face of the tube according to the combination of potentials applied to said plates, and a plurality of tabs on the face of the tube each arranged to provide an output when the electron beam impinges thereon.

6. A cathode ray tube for processing digital data comprising means for forming a sheet beam and accelerating said beam toward the face of the tube, an electron lens system, means for applying voltages to said lens for developing a focusing field for focusing the electron beam onto the face of the tube, said lens system comprising three apertured lenses positioned transversely to the electron beam, first apertured stop means positioned intermediate the first and second of said lens in a plane in which said field forms a straight line between the lens so as not to affect the field distribution and thus the focusing action of said lens, the size of the aperture in said stop means being equal to twice the distance between said first and References Cited in the file of this patent UNITED STATES PATENTS Josephson et a1. Sept. 27, 1955 Speedy Jan. 24, 1956 McNaney Oct. 29, 1957 Adler Jan. 14, 1958 McNaney Oct, 6, 1959 Keeran Feb. 16, 1960 De Haan June 7, 1960 

1. A CATHODE RAY TUBE FOR PROCESSING DIGITAL DATA COMPRISING AN ELECTRON GUN INCLUDING A CATHODE, A PAIR OF PLATES POSITIONED AT AN ACUTE ANGLE WITH THE PLANE OF THE CATHODE FOR FORMING A SHEET BEAM, SAID PLATES BEING SPACED FROM SAID CATHODE, MEANS FOR SAID PLATES BEING ARRANGED FOR PROVIDING ON-OFF CONTROL OF THE EMISSION FROM SAID CATHODE, MEANS FOR ACCELERATING THE ELECTRON BEAM, AN ELECTRON LENS SYSTEM FOR DEVELOPING A POTENTIAL FIELD FOR FOCUSING THE ELECTRON BEAM ONTO THE FACE OF THE TUBE, SAID LENS SYSTEM COMPRISING AT LEAST THREE APERTURED LENSES POSITIONED TRANSVERSELY TO THE ELECTRON BEAM, FIRST APERTURED STOP MEANS POSITIONED INTERMEDIATE THE FIRST AND SECOND OF SAID LENS, SECOND APERTURED STOP MEANS POSITIONED INTERMEDIATE THE SECOND AND THIRD OF SAID LENS, SAID STOP MEANS BEING POSITIONED SO AS NOT TO DISTURB THE FOCUSING FIELD DEVELOPED BY SAID LENS, A PLURALITY OF ELECTRON BEAM DEFLECTING PLATES FOR CONTROLLING SAID BEAM TO IMPINGE AT SELECTED POINTS ON THE FACE OF THE TUBE, SAID PLURALITY OF PLATES BEING POSITIONED IN SPACED RELATION IN A TRUNCATED-CONE-LIKE ARRANGEMENT WITH A ROW OF TWO DEFLECTING PLATES FORMING THE NARROW END OF THE CONE AND BEING POSITIONED ADJACENT THE LENS SYSTEM, A ROW CONTAINING THE LARGEST NUMBER OF DEFLECTING PLATES POSITIONED ADJACENT THE FACE OF THE TUBE, SAID DEFLECTING PLATES PROVIDING A TRANSFER TREE TYPE OF DEFLECTION IN WHICH THE ELECTRON BEAM IS ROUTED TO ANY ONE OF A PLURALITY OF POINTS ON THE FACE OF THE TUBE ACCORDING TO THE COMBINATION OF POTENTIALS APPLIED TO SAID PLATES, AND A PLURALITY OF ANODE TABS ON THE FACE OF THE TUBE EACH ARRANGED TO PROVIDE AN OUTPUT WHEN THE ELECTRON BEAM IMPINGES THEREON. 